p2371: Remove hard-coded counter frequency

The counter frequency is derived from clk_m on Tegra, but that clock can
be configured by the primary bootloader to run at the same frequency as
the oscillator (38.4 MHz on Tegra210) or a divided down frequency (most
typically 19.2 MHz). Remove the hard-coded frequency and allow the timer
setup code to query the correct value at runtime.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>

include/configs/p2371-0000.h

@@ -59,7 +59,4 @@
 #include "tegra-common-usb-gadget.h"
 #include "tegra-common-post.h"
 
-/* Crystal is 38.4MHz. clk_m runs at half that rate */
-#define COUNTER_FREQUENCY	19200000
-
 #endif /* _P2371_0000_H */